Pinpoint Test G: The EATC System is Inoperative, Intermittent or Incorrect Operation
Normal Operation
NOTE:
Possible Causes
For a complete explanation of the EATC system functions, refer to description and operation in CONTROL COMPONENTS.
Under normal operation, the EATC module receives a ground through circuit 875 (BK/LB). The EATC module is supplied constant battery voltage through circuit 729 (RD/WH) and ignition switched voltage through circuit 296 (WH/VT).
An open in circuit 875 (BK/LB), 729 (RD/WH) or 296 (WH/VT) EATC module
PINPOINT TEST G: THE EATC SYSTEM IS INOPERATIVE, INTERMITTENT OR INCORRECT OPERATION
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G1 VERIFY AUTOMATIC OPERATION Key in ON position. With engine running, press the AUTOMATIC button. Does the indicator above the AUTO button illuminate and the selected temperature appear in the display window? à † Yes : GO to G2. à † No : GO to G11. G2 CARRY OUT THE EATC MODULE SELF-TEST Key in ON position. Carry out the EATC module self-test. Refer to the ELECTRONIC AUTOMATIC TEMPERATURE CONTROL MODULE ON-DEMAND SELF-TEST. Record the DTCs displayed, if any. Were any DTCs displayed as a result of the EATC self-test? à † Yes : REFER to the ELECTRONIC AUTOMATIC TEMPERATURE CONTROL (EATC) MODULE DIAGNOSTIC TROUBLE CODE (DTC) INDEX. CARRY OUT the necessary diagnosis and REPAIR as required. à † No : GO to G3. G3 CHECK THE VACUUM FLUORESCENT DISPLAY Exit the self-test by pressing the DEFROST button. Observe the button indicators and function symbols displayed on the vacuum fluorescent display while changing the temperature, blower speed and functions. Are the display and indicators correct and complete without any missing elements? à † Yes : GO to G4. à † No : INSTALL a new EATC module. REFER to CONTROL COMPONENTS. TEST
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the system for normal operation. G4 CHECK THE BLOWER MANUAL OVERRIDE OPERATION Press the blower motor speed override control fully up and fully down. Does the blower motor speed increase from low speed to high and high speed to low? à † Yes : GO to G5. à † No : If the blower motor is inoperative, GO to PINPOINT TEST M.
The blower motor does not operate correctly, GO to PINPOINT TEST N.
G5 VERIFY THE DEFROST OVERRIDE OPERATION Press the override button for DEFROST operation. Is outside air being discharged from the windshield defroster nozzle and the side window demisters? à † Yes : GO to G6. à † No : GO to PINPOINT TEST D. G6 VERIFY THE FLOOR OVERRIDE OPERATION Press the override button for FLOOR operation. Is outside air being discharged from the floor duct? à † Yes : GO to G7. à † No : GO to PINPOINT TEST D. G7 VERIFY THE PANEL OVERRIDE OPERATION Press the override button for PANEL operation. Is outside air being discharged from the instrument panel registers? à † Yes : GO to G8. à † No : GO to PINPOINT TEST D. G8 VERIFY THE A/C CLUTCH DOES NOT ENGAGE IN THE PANEL MODE In PANEL operation and the A/C OFF, listen for the compressor clutch to engage. Does the A/C clutch engage with the PANEL override button pressed? à † Yes : GO to PINPOINT TEST J. à † No : GO to G9. G9 VERIFY A/C CLUTCH ENGAGEMENT IN THE A/C MODE Make sure the ambient air temperature is above 2 °C (35 °F). Press the override button for A/C operation. Does the A/C clutch engage when the A/C override button is pressed? à † Yes : GO to G10. à † No : GO to PINPOINT TEST I. G10 VERIFY THE RECIRC OVERRIDE OPERATION Press the PANEL and RECIRC override buttons. Is recirculated air being discharged from the instrument panel registers? à † Yes : The test is complete. The system is functioning normally.
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Fig. 73: Measuring Resistance Between EATC Module C228a-1, Circuit 875 (BK/LB) And Ground Courtesy of FORD MOTOR CO.
Is the resistance less than 5 ohms?
Fig. 74: Measuring Voltage Between EATC Module C228a-26, Circuit 729 (RD/WH), C228a-14, Circuit 296 (WH/VT) And Ground Courtesy of FORD MOTOR CO.
Is the voltage greater than 10 volts?
à † No : GO to PINPOINT TEST C. G11 CHECK THE EATC MODULE FUNCTIONS Press each function button and observe the display. Does the EATC carry out and display any functions? à † Yes : INSTALL a new EATC module. REFER to CONTROL COMPONENTS. TEST the system for normal operation. à † No : GO to G12. G12 CHECK CIRCUIT 875 (BK/LB) FOR AN OPEN Key in OFF position. Disconnect: EATC Module C228a. Measure the resistance between EATC module C228a-1, circuit 875 (BK/LB) and ground.
à   à † Yes : GO to G13. à † No : REPAIR circuit 875 (BK/LB). TEST the system for normal operation. G13 CHECK CIRCUITS 729 (RD/WH) AND 296 (WH/VT) FOR AN OPEN Key in ON position. Measure the voltage between EATC module C228a-26, circuit 729 (RD/WH), C228a-14, circuit 296 (WH/VT) and ground.
à   à † Yes : INSTALL a new EATC module. REFER to CONTROL COMPONENTS. TEST the system for normal operation. à † No : REPAIR circuit 729 (RD/WH) or 296 (WH/VT) for an open. TEST the system for normal operation.
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This is the on demand self test, I doubt it will work if the panel is dead, but if you get the panel back using the guide above, run this to check for any codes.
The EATC module on-demand self-test will detect concerns in the system control functions and will display on-demand (hard fault) DTCs for concerns that are present during the self-test. The vehicle interior temperature should be between 4 °C - 38 °C (40 °F - 100 °F) when performing the self-test. If the temperatures are not within the specified ranges, false DTCs may be displayed. The self-test can be initiated after cycling the ignition switch from OFF to ON. Normal operation of the climate control system stops when the self-test is activated. To enter the self-test, press the OFF and DEFROST buttons simultaneously and release, then press the AUTO button within 2 seconds. The display will show a flashing blower icon for 20 seconds, after which all vacuum fluorescent segments will be displayed if there are no on-demand DTCs present. If DTCs are present the EATC module will display "00 00" and then on-demand DTCs. Record all DTCs displayed.
Saturday, April 17th, 2010 AT 6:28 PM
